[Hallicrafters] SX-115 Sensitivity

[Bill Gerhold]

Interesting Tom.  I have an SX-111 that suffers the same problem.  80 and 40
meters is fine, 20 meters a little less and the receiver gets real bad.  I
did the same things you did with very little improvement.  I decided it is
the way the receiver is and with that, added an outboard preamp.  The solved
the problem handily but still leaves me with a guilty feeling that I did not
solve the problem and am just going around the problem the lazy mans way.

Anyway, if you are interested, I bought a very small solid state preamp that
is broad banded from 1-30 mhz and makes a big difference.  It is made by
Advanced Receiver Research.  It is small, about 2" square and about 1/2"
thick and runs on 12vdc.  I got it with RCA connectors and just put it in
the antenna line.  It's like having a new receiver.

I do not feel bad about doing it after asking this forums members about
adding a preamp to these old receivers and the majority say it should be
done whenever necessary.  They have a website, do a google search for it and
look for the broadband unit I described.  I think they are about $ 40.00.
You will be pleasantly surprised.

K2WH

-----Original Message-----
From: hallicrafters-bounces at mailman.qth.net
[mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Tom Elmore
Sent: Saturday, April 30, 2005 4:41 PM
To: hallicrafters at mailman.qth.net
Subject: [Hallicrafters] SX-115 Sensitivity

  I have an SX-115 that seems to have lost it's sensitivity on 40 through 10
meters. The 80 meter specs out about 1/2 microvolt using my service monitor
and starting at 40 meters it is around 1 microvolt, at 20 meters it is about
2 to 3 and get worse the higher up I go in frequency. I have re-peaked the
coils in the front end and mixer with very little improvement. I have also
changed out the RF amp tube in the front end and the mixer tube and get the
same results. Anyone else run into this situation ?

Thank You
Thomas Elmore KA1NVZ
Anchorage, Alaska

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